LT1-LT4 Modifications 1993-97 Gen II Small Block V8

please help me with this issue!

Thread Tools
 
Search this Thread
 
Old Jun 10, 2012 | 04:12 PM
  #1  
BadBirdie's Avatar
Thread Starter
Launching!
 
Joined: Feb 2012
Posts: 281
Likes: 0
From: IL
Default please help me with this issue!

hopefully this is easily identifyable as there are some unique clues.

1. this problem was happening about a month ago after i drove through rain, but until yesterday the car ran great for about a month like i said, then started doing the same thing yesterday and it did not get wet.

2. my ses light is always on due to the rear o2s not being tuned out, but during this issue the ses light is flashing.

ok so the car starts up just fine everytime, there is no issue there. after about 5 mins of driving the car stumbles bad and struggles to get above 30 mph, feels like a really bad miss. stopped at a light the rpms drop to 400-500 when they are normally 900 on my car. standing next to the car and reving in neutral you can hear it backfire. it has not completely died on me yet so that should also narrow down possibilities.

last night i tried driving home from work and the car started acting up like this so i pulled over about 2 blocks from my work and left the car there overnight. im going back later today to try and drive it the rest of the way home.

from the reading i've done it seems like the culprits are:
opti
coil
icm
fuel pump

HELP!
Reply
Old Jun 10, 2012 | 06:03 PM
  #2  
SilverSS07's Avatar
TECH Regular
iTrader: (1)
 
Joined: Dec 2010
Posts: 411
Likes: 1
From: Ocala Florida
Default

See what the other trouble codes are. It's easy to check fuel pressure with a gauge. I would think it's ignition though and the SES is probably flashing because of a misfire. You could check the ohms on the coil and visually look for any burned plug wires or anything.
Reply
Old Jun 10, 2012 | 06:32 PM
  #3  
TimmyZ28's Avatar
Teching In
 
Joined: Jun 2012
Posts: 48
Likes: 0
From: Poconos, PA
Default

SES flashing is indicating that the car is misfiring. Backfire is usually a timing thing or an ignition misfire. It's possible that optispark just went out on you but make sure to check everything else. Fouled plugs, hold the coil wire near the coil terminal to see it arc indicating spark at that point.
Reply
Old Jun 10, 2012 | 07:22 PM
  #4  
BadBirdie's Avatar
Thread Starter
Launching!
 
Joined: Feb 2012
Posts: 281
Likes: 0
From: IL
Default

well i just went and picked up the car and drove it about 7 miles home and didnt see any problems. i shut it off in my driveway so i could move another car out of the garage so i could pull it in and get it up on jack stands. when i restarted it i had the issue again flashing ses light and low idle.

this is exactly what was happening a month ago, sometimes when i started it it would run fine until i shut it off. other times i would start it and put it in drive and missfire like crazy.

glad to hear a flashing ses light means missfire so hopefully i can rule out a bad fuel pump.

im letting the car cool down on jack stands now, later i'll inspect the plugs and wires and connections at the opti and coil. i have a HEI spark tester i bought a month ago when i first encountered this problem, but then it "went away"
Reply
Old Jun 10, 2012 | 07:50 PM
  #5  
Bigtoyz's Avatar
Launching!
iTrader: (2)
 
Joined: Apr 2012
Posts: 219
Likes: 1
Default

I dont know if it is kind of the same issue or not. But my car has been kind of hard starting all of a sudden. Just needed to crank little bit more than normal, but still started.

Well I went to take my car to be tuned. Had to stop and a store for the wife first. Went to start the car and wouldnt start. Didnt hear the pumps prime up. So thought it was the relay. bypassed the relay and pump ran. But pressure went up to 60 psi so I tried starting it. It wouldnt so I figured it maybe flooded. So we pulled it to where it needed to go. A buddy of mine mentioned he has fixed some blazers with same kind of issue but was the oil pressure switch that cuts off fuel if you have a roll over when you loose oil pressure to stop fuel fires.

Does anyone know where this is located to test. And maybe it could be your issue also. Didnt mean to get off topic if isnt.....
Reply
Old Jun 10, 2012 | 08:27 PM
  #6  
Bigtoyz's Avatar
Launching!
iTrader: (2)
 
Joined: Apr 2012
Posts: 219
Likes: 1
Default

Found where it is at in back of the intake underneath the fuel reg.
Reply
Old Jun 10, 2012 | 09:41 PM
  #7  
BadBirdie's Avatar
Thread Starter
Launching!
 
Joined: Feb 2012
Posts: 281
Likes: 0
From: IL
Default

after checking all the connections to spark plugs and to opti, all plugs are tight, wires are in good condition. connections all seem good however i did notice some residue on the wires where they connect to the opti on the passenger side that might have been coolant leaking from the water pump. this is my dd so im going to have to start throwing parts at it unless someone can help.
Reply
Old Jun 10, 2012 | 10:01 PM
  #8  
SilverSS07's Avatar
TECH Regular
iTrader: (1)
 
Joined: Dec 2010
Posts: 411
Likes: 1
From: Ocala Florida
Default

Find out what the codes are; that should help some. ICM you should be able to have tested at a parts store. Ohm the plug wires to make sure they're good. Inspect spark plugs. Ohm coil. There's a thread on here of how to diagnose the opti. Do that.
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-1

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-2

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-3

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-4

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-5

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-6

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-7

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-8

10 Camaros You Should Never Buy

 
story-9

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo
Old Jun 10, 2012 | 10:49 PM
  #9  
Catmaigne's Avatar
TECH Fanatic
10 Year Member
Photogenic
iTrader: (6)
 
Joined: May 2011
Posts: 1,241
Likes: 25
From: Conshohocken, PA
Default

Scan before you jump to conclusions. It could be something as small as an O2 sensor.
Reply
Old Jun 10, 2012 | 11:02 PM
  #10  
mezzyshreder's Avatar
Staging Lane
 
Joined: Feb 2012
Posts: 81
Likes: 0
From: nj
Default

Scan for codes before you do anything.
Reply




All times are GMT -5. The time now is 08:20 PM.

story-0
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-1
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-2
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-3
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-4
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-5
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-6
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE